I've read a lot of discussions about this problem but I still have questions.
After replacing the intake I still had a "engine too lean code" I've searched for a vac leak and finally gave up. Not long after that the truck (2001 Expedition) began stalling at lights. It will not idle for more than a few minutes.

On the advice of many forums I changed the throttle position sensor and the idle air controller. - NO CHANGE

Otherwise the truck runs great in all respects, plenty of power, cruises effortlessly, and gets the usual mileage - 13-4 MPG (and I drive like a teenager)

So, I think the vac leak that might be causing the "engine tool lean" code is not very severe. I've been driving it like this for about 10,000 miles.

From what I've read the most likely culprit for the stalling problem is still the idle air controller and I have read that they often come bad from the parts store. But before I change it again I would like to get a better understanding of the variables.

Is there a way to troubleshoot the IAC?


Thanks